Langenfeld



Sept. 24, 1963 c. LANGENFELD 3,104,797

FLEXIBLE COMMODITY BAGS AND APPARATUS FOR PRODUCING SAME Filed June 23, 1960 2 Sheets-Sheet l PRIOR ART INVENTOR CLAUDE LANGENFELD ATTORNEY Sept. 24, 1963 c. LANGENFELD 3,10 7

FLEXIBLE COMMODITY BAGS AND APPARATUS FOR PRODUCING SAME Filed June 23, 1960 2 Sheets-Sheet 2 INVENTOR J I CLAUDE LANGENFELD ATTORNEY United States Patent Milprint, inc, Milwaukee, Wis., a corporation of Delaware Filed June 23, 1960, Ser. No. 38,144 2 Claims. (Cl. 229-53) The present invention relates in general to improvements in the art of manufacturing commodity packages and is more particularly directed to an improved curt-off knife mechanism for use in conventional bag making machines for separating lengths of tubular stock into bag-forming sections, wherein the improved knife includes opposed auxiliary blade members arranged to separate inwardly folded areas of material from the main bag stock wherein the tubuiarly formed stock is adapted for manufacture of bags having opposed in-folded margins to provide pleats or gussets.

The principal object of the present invention is to provide an improved commodity confining bag having one end sealed by means of heat sealing or other means, wherein there is greater area contact between the end folded, adhering portions, by having certain inwardly folded layers separated therefrom in such manner as to permit better glue application at the bottom of the bag and a better heat seal because of omission of materials tending to interfere with the conductance of heat from the sealing tool to the area of adhesion.

It has been heretofore well known procedure to produce successive bag-like receptacles for diverse commodities from a web of flexible stock by initially folding the longitudinally advancing web into flat tubular formation, and wherein the tube also includes opposed inwardly folded sides defining pleats or gussets, and by thereafter sealing the overlapped edges of the web to provide a longitudinal seam and severing the tube transversely into desirable lengths, and by finally folding an end of each severed length against the body of the tube and securing the fold to the outer body surface adjacent to the fold line so as to provide a closed bag bottom. It is also well known to coat a transverse adhesive strip adjacent the bottom fold, which adhesive is of a heat sealable type.

However, the usual arrangement for applying adhesive, folding and then later heat sealing, especially in the case of wax bags having marginal gussets, has often been somewhat undesirable in its sealing characteristics. That is, too often there was too much material between the sealing tool and the adhesive or heat sealable material which interfered with good heat conductance to provide the desired seal. In addition, this material generally was left at :the opposed side margins and interfered with the application of adhesive throughout the entire transverse width of the bag. Very often, unless very close attention was paid to the end seal, an improperly sealed bag would later be filled with a commodity and either during shipping, or when placed in a rack in a store, the weight alone of the commodity would tend to open the seal. This is particularly true of the side margins of the sealed area where proper adhesion is most important;

Also, in the case of bags having infolded gusseted margins, there are often jam ups in the folding and sealing equipment because of less slack control by reason of the fact that there was no provision for guiding the infolded material as it passed through the cut-off knife mechanism.

It is therefore an important object of the present invention to provide an improved cut-off knife mechanism for separating tubular stock into bag-forming sections, which knife is adapted to provide an improved bottom known manner.

edge for an improved seal, and which additionally provides guide means for the tubularly formed material as it passes therethrough, whereby jam ups are substantially obviated.

Another important object of the present invention is to provide an improved commodity bag capable of retaining its bottom seal under any and all circumstances by virtue of better seal application established by reason of a new and novel bottom tr-im configuration.

It is a further object of the present invention to provide an improved seal for gusset-type commodity bags, wherein greater surface sealing area is provided by elimination of interfering portions of intermediate layers of infolded bag portions, whereby escape of the bag contents is avoided because of adequate sealing thereof.

These and other specific objects and advantages of the invention will be apparent from the following'description of an illustrative embodiment of the invention, taken in connection with the drawings, wherein:

FIG. 1 is a diagrammatic side view of a typical bag forming machine including the improved lip-type cutoff knife mechanism of the present invention, with supporting frame portions eliminated therefrom for clearness of illustration;

FIG. 2 is a plan view of a fragment taken between lines 2-2 of FIG. @1 of a web converted into ilat tubular formation :and showing the location of the lines of severance for segregating the tube into the successive bag lengths;

FIG. 3 is a fragmentary perspective View of the bottom portion of a typical bag formed prior to the conception of .the present invention, and presented as an aid in illustrating the improved edge configuration of the present invention;

FIG. 4 is a fragmentary perspective view, similar to the view of FIG. 3, of the bottom portion of one of the improved bag-like receptacles;

FIG. 5 is a fragmentary perspective view of the bag bottom made in accordance with the present invention illustrating the bottom end flap folded into sealing position, and with one corner turned back to show the relationship thereof with the transverse adhesive sealing strip;

FIG. 6 is a plan view with portions broken away of the improved cut-off knife mechanism of the present invention and with a tubularly formed section being inserted between components thereof;

FIG. 7 is a front elevational view of the segregating knife mechanism components of the present invention with tubular stock inserted therebetween and in position immediately after having been severed;

FIG. 8 is a fragmentary sectional view taken along lines 7-7 of FIG. 7;

FIG. 9 is a fragmentary plan view of the tooth formation of each of the respective knife blades forming the knife mechanism of the present invention.

Referring to the drawings, and particularly FIG. 1 thereof, a Web 10 of a material, such as waxed glassine paper, is initially withdrawn from the supply roll 11 by means of draw rolls (not shown) in customary and well As the web lfltis longitudinally advanced about the guide roll 12, thermoplastic adhesive material is transferred by means of the rolls 13 and 14. Tahe'thermoplastic adhesive material is applied to one of the longitudinal edge portions, and the web 10 containing the longitudinal strip of thermoplastic material is thereafter folded by means of a suitable former 15 in a known manner to form a tube with a longitudinal edge portion overlapping, and these overlapping edge portions are then sealed by means of a heated longitudinal sealing bar or plate 16 to provide the seam '17 (see FIGS. 2, 4 and 5). The draw rolls 18 coact with the tube thus formed and with the longitudinally extending forming plate 19 to advance the tube to the knife mechanism 2i) comprising the present invention, and which mechanism acts thereupon in conjunction with a rotating striker arm or bar 21 to sever the tube in a manner which will hereinafter be described.

It is to be noted that the main frame and stationary support members for the various moving elements has been omitted from the view of FIG. 1 for simplicity of illustration and description. 7

The tube sections 22 severed from the web by means of the knife mechanism 20 and the bars 21 are advanced by means of driven rolls 23 to the periphery of a first cylindrical carrier member 24 rotatable in the direction of the arrow.

The leading end of each tube section 22 is simultaneously tucked and clamped to the periphery of the carrier member 24 by a peripheral clamp 27, and simultaneously therewith, a transverse strip of thermoplastic adhesive material 3%) is applied to the leading end of the tube section 22 by means of a transfer mechanism 28 receiving thermoplastic from the transfer roll 29, the transverse adhesive strip 39 being indicated in the form of stippling at 30 in the view of FIG. 4.

As the cylindrical (carrier member 24 is rotated, the clamp 27 carries the section 22 therewith and one or more resiliently mounted guide and folding fingers 31 coact with the end portion of the section 22 to fold the same at 32 over the transverse thermoplastic adhesive strip 30. From the carrier member 24, each section 22 is then transferred to a second carrier member 35 rota-ting in an opposite direction as indicated by the arrow in FIG. 1. provided with transverse heating elements or bars 36 carried thereby and cooperable with the folded portion32 of the tube section 22 for subjecting this portion to heat transversely thereacross throughout the travel of the tube section with the second carrier member 35. Throughout the heating operation and during the contact of the heating element 36 with one side of the tube section, one or more flexible belts 37 guided about a series of pulleys 33 coact directly with the other side of the tube section 22 in opposition to the beat applying means to simultaneously apply resilient pressure thereto. From the carrier member 35, each tube section 22 is conducted between a pair of cooperating endless belts 40, 41 operating about guide pulleys 4'2, 43, respectively, along a sinuous path formed by cooperating guide rolls 44, 45, and the path formed by the cooperating belt 40, 41, preferably terminating in a direction toward the carrier members 24, 35, at which point tube sections are each discharged into a suitable stacker 46 as completed bags. To positively transfer each of the successive tube sections 22 from the periphery of the cylindrical carrier member 35, one or more elongated and flexible elements, such as narrow belts 47 may be provided, the belt or belts 47 being recessed with suitable peripheral grooves (not shown) formed in the cylindrical carrier member 24 and traveling therewith between the periphery of the carrier member 24 and the successive tube sections 22, and then being guided with the successive tube sections about the periphery of the cylindrical carrier member 35 externally of the section 22.

Attention is now directed to the improved bag configuration illustrated in the views of FIGS. 2, and 6 and to the cut-off knife mechanism 20, of the present invention as particularly illustrated in FIGS. 6-9, which mechanism may be used in the above-described bag making machine or in any comparable machine.

The lip-type cut-01f knife mechanism 20 of the present invention is supported by the main frame (not shown) by means of a stationary support member 50 arranged to pivotally support the knife mechanism 26 from one end thereof, as shown in FIGS. 6 and 7. The mechanism 20 includes a transversely slotted knife holder 51 supported The second cylindrical carrier member is respective ones of its radially extending arms 76.

4 at its opposite end by a stationary frame member 52, and retained in place by means of a releasable latching clip 53. The clip 53 further acts to maintain the knife mechanism 20 in alignment relative to the longitudinal axis of the moving folded tubular web 10. The top. knife blade 54 and auxiliary knife blades 55 and 56 are maintained in place upon disposition of the top knife blade 54 at the underside of the knife holder 51, and retaining the same in place by means of nut and =bolt as' semblies 57 and 58, as may be seen from the View of FIG. 5. The knife blade 54 is provided with transverse slots 59 and 60 for slidably adjustable engagement with the knife holder 51 by means of the nut and bolt assemblies 57 and 58, respectively. Other slots 61 are provided wherein knife holders of various sizes may b utilized depending upon the type of machine. The present knife mechanism 20 is adaptable for use on any of the well-known and commercially available bag making 7 machines, and may be modified for use with any machine The knife blade 54 is provided with longitudinally di sposed slots 62 and 63 arranged to slidably receive adjusting thumb screws 64 and 65, respectively. The thumb screws 64 and 65 engage tapped openings in the auxiliary knife blades 55 and 56, respectively, and serve to hold the respective knives tightly against the blade 54 bymeans of lock washers 66. A further retaining or stop means is provided in the form of a pin 67, which maybe sweated in place in a drilled hole in each of the respective blades 55 and 56, and which pins serve to prevent the respective blades from rotating about the thumb screw 54 upon engagement of the pin with the slots 62 and '63, respectively. It will be apparent that the auxiliary knife blades 55 and 56 are longitudinally adjustable relative to the top blade 54, and to each other by means of the cooperative releasable relationship between the respective thumb screws 64 and 65 and the elongated slots 62 and 63.

The forming plate 19 extends longitudinally of the travel of the web 10 and beyond the top knife blade 54,-

and is provided with cutting teeth at its outer end to shear off the exposed edge 71 of the section 22 as shown in FIG. 2. The knife blade 54 may be adjusted in its slots 59 and 69 by loosening the bolt and nut assemblies 57 and 58 to provide the desired amount of exposed carrier bag marginal surface for adhesion to the outer bag surface after folding. The toothed edge of the top knife blade 54 acts to shear the edge 72 and the adjustable auxiliary blades 55 and 56 are adapted to cut the edges 73 and 74 of the infolded layers, respectively. The cutting action is accomplished by means of the coaction of the continuously revolving striker arm or blade mechanism 21 and The arms 76 are arranged to strike the continuously moving tubularly formed web 10 and cut it into the sections 22 as the bag sections are respectively forced against the knives 54, 55, 56 and the edge of the forming plate 19. FIG. 8 is illustrative of the shape of the teeth 77 formed in each of the respective blades. it will be noted that the adjustable auxiliary blades 5 and 56 are recessed at 78 and 79, respectively. Thus,

the inwardly folded margins or gussets 80 of the sections 22 may be disposed in a sinuous path about the forming plate 1? and the inwardly projecting recessed portions of the blades 55 and 56 to permit certain portions of the bag to be specifically separated from the remaining bag area in accordance with the present invention. Such knife blade configuration permits selective trimming and also acts as a guide for the web 10 as it moves through the knife mechanism 20, thereby preventing former problems of jam up in the folding and sealing equipment because of relatively little slack control. Heretofore, the blades comprised only two coacting blade members, similar to the top blade 5'4 and the edge of the forming plate 19, which respectively sheared the edges 85 and 86 of the older type bag shown in FIG. 3.

It will thus be apparent that as the tub-ularly formed web it: encircling the fiat forming plate 19, moves longitudinally away from the sealing bar 16, it passes between the respective blades of the knife mechanism 29 in the manner shown in FIG. 7. That is, the inwardly folded portions defining the pleat or gusset 8t} surround the forming plate 19 at the bottom part of the respective sinuous folds and reverse in their fold about the recessed inwardly extending knife blade portions 78 and 79 of the knife blades 55 and 56, respectively, and then with another reverse fold to define the upper layer of the tubnlarly formed web 19. Thus, it will be apparent that the teeth of the adjustable knife blades 55 and 56 are arranged to act individually upon certain areas of the tubular web as the arms 76 of the striker mechanism 21 rotate in the direction of the arrow and thereby act to tear the individual sections 22 therefrom.

It will be appreciated from the View of FIG. 3, that heretofore, bags separated by means of two coacting knife edges such as a single knife blade and the edge of the forming plate left considerable uncut material, such as the areas designated 87 and 88 prior to folding on the fold line 89. It will be apparent that considerable bag surface defined by the areas '87 and 88 would be interposed between the heating elements 36 of the carrier member 35 (see FIG. 1) and the adhesive strip 30 to thereby interfere with proper sealing at the most critical portions of the -bagthe outer mar-gins. In fact, in order to provide a proper heat seal at these areas the portion intermediate the areas 37 and 88 would very often be overheats Obviously, heat control became extremely important and required considerable attention by highly paid, skilled labor.

In the present case, and with reference to FIGS. 4 and 5, the blades 55 and 56 may be arranged to cut most of the inwardly folded portions 95 and 96 away from the bottom layer to thereby provide excellent adhesive characteristics along the entire transverse adhesive strip 3%. Thus, in the present knife mechanism, the auxiliary blades 55 and 56 act in a dual capacity. That is, the in-folded pleat or gusset portions 80 surround the respective blade recessed portions 77 and 79, the tubular Web Ill being thereby guided in its travel through the knife mechanism 20, and in proper alignment for the rotating beater or striker arms 7i: to act thereupon for severing the web 16 into bag sections 22. It will thus be apparent from the plan view of FIG. 2 that the blades 54-56 and the knife edge of the forming plate 19 separate the web into top and bottom portions of the bag, as defined by the edges 7144, inclusive. The top knife blade 54, in the present construction provides a straight transverse cut defining the edge '72, to thereby expose considerable area for purposes of greater adhesive contact, compared to that defined by the curved ends of the edge 85 of the former bag construction illustrated in FIG. 3.

When the bag 22 of the present invention is folded along its transverse fold line 79, there is substantially less material interposed between the heat sealing tool 16 and the adhesive material 34), as will be apparent from a comparison of FIG. 3 with the present bottom edge configuration of FIGS. 4 and 5. In fact, it will be observed that the areas 87 and 88 of the former bag defined an additional two layers interposed between the sealing tool it? and the adhesive material 3%. Such layers are very often of relatively poor heat-conductive material, as in the case of waxed glassine bags. Thus, in the present embodiment, when the bag 22 is folded along its transverse fold line 70, the gusseted margins themselves, are directly sealed to the adhesive 39, and thereby obviate the problem of the former bag construction wherein the side margins often become tangled with those of adjacent filled bags, or with other objects tending to break the seal from the bottom flap portion. It will be apparent that the top portion of the bag may be sealed in any known manner after the bag has been filled with the commodity intended to be contained therein.

It will he observed from the foregoing description that the present invention has provided an improved apparatus for making bags, and particularly gusseted bags, in which the adhesive characteristics are greatly enhanced and in which mechanism provides a further guide for transportation of the tubular bag forming material through a conventional bag making machine.

I claim:

1. In a bag having substantially planar front and rear faces connected at their side edges by gusseted side panels, an end-seal comprising:

a closure flap made up of a portion of the bag material adjacent the end to be sealed and adapted to be folded rearwardly about a transverse fold line to engage the rear face of said bag;

the rear face of said bag material in said closure flap being shorter than said front face to expose a substantial portion of an interior surface of said front face;

a part of the gusseted side panels not contiguous with said rear face of said bag material in said closure flap being cut approximately the same length as and substantially parallel to said rear face;

the exposed interior surface of said face of the bag material in said closure flap being adhesively bonded to said rear face of said bag. a

2. In a bag having substantially planar front and rear faces connected at their side edges by gusseted side panels, and end-seal comprising:

a closure flap made up of a portion of the bag material adjacent the end to be sealed and adapted to be folded rearwardly about a transverse fold line to engage the rear face of said bag;

the rear face of said bag material in said closure flap being shorter than said front face to expose a substantial portion of an interior surface of said front face;

a part of the gusseted side panels contiguous with said rear face of said bag material in said closure flap being cut approximately the same length and substantially parallel to said rear face;

the exposed interior surface of said front face of the bag material in said closure flap being adhesively bonded to said rear face of said bag.

References Cited in the file of this patent UNITED STATES PATENTS 820,071 Smith May 8, 1906 1,747,189 Seller Feb. 18, 1930 1,887,680 Hallman Nov. 15, 1932 1,970,848 Grant Aug. 21, 1934 2,237,327 Bell Apr. 8, 1941 2,945,616 Normandin July 19, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,104,797 September 24, 1963 Claude Langenfeld It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 9, for "construction" read constructions line 38, before "face" insert front Signed and sealed this 25th day of February 1964.

(SEAL) Attcst:

ERNEST W. SWIDER E. WIN L. REYNOLDS 

1. IN A BAG HAVING SUBSTANTIALLY PLANAR FRONT AND REAR FACES CONNECTED AT THEIR SIDE EDGES BY GUSSETED SIDE PANELS, AN END-SEAL COMPRISING: A CLOSURE FLAP MADE UP OF A PORTION OF THE BAG MATERIAL ADJACENT THE END TO BE SEALED AND ADAPTED TO BE FOLDED REARWARDLY ABOUT A TRANSVERSE FOLD LINE TO ENGAGE THE REAR FACE OF SAID BAG; THE REAR FACE OF SAID BAG MATERIAL IN SAID CLOSURE FLAP BEING SHORTER THAN SAID FRONT FACE TO EXPOSE A SUBSTANTIAL PORTION OF AN INTERIOR SURFACE OF SAID FRONT FACE; A PART OF THE GUSSETED SIDE PANELS NOT CONTIGUOUS WITH SAID REAR FACE OF SAID BAG MATERIAL IN SAID CLOSURE FLAP BEING CUT APPROXIMATELY THE SAME LENGTH AS AND SUBSTANTIALLY PARALLEL TO SAID REAR FACE; THE EXPOSED INTERIOR SURFACE OF SAID FACE OF THE BAG MATERIAL IN SAID CLOSURE FLAP BEING ADHESIVELY BONDED TO SAID REAR FACE OF SAID BAG. 